Using a new model relating dislocation charge to Fermi level, we have simulated the differential capacitance resulting from the inclined dislocations accompanying the misfit dislocations in epitaxial InGaAs/InP samples. The result is a quadratic dependence of charge upon mismatch which is in quantitative agreement with experiments of Macranderetal. for a misfit dislocation segment length equal to about nine times the dislocation spacing.